Date Added: May 2013
In this system, each user needs to visit a Private Key Generation (PKG) and identify him-self before joining a communication network. Once a user is accepted, the PKG will provide him with a secret key. In this way, if a user wants to communicate with others, he only needs to know the \"Identity\" of his communication partner and the public key of the PKG. There is no public file required in this system. In this paper, the authors propose an Identity Based Encryption (IBE) based on the Integer Factorization Problem (IFP) and Double Discrete Logarithm Problem (DDLP) and they consider the security against a conspiracy of some entities in the proposed system and show the possibility of establishing a more secure system.